Vegetation Changes Associated With Invasion by Phytophthora cinnamomi on Monitored Sites in the Grampians, Western Australia

1986 ◽  
Vol 34 (3) ◽  
pp. 251 ◽  
Author(s):  
J Kennedy ◽  
G Weste
Keyword(s):  
Species Composition ◽  
Endemic Species ◽  
Plant Density ◽  
Phytophthora Cinnamomi ◽  
Soil Surface ◽  
Tree Canopy ◽  
Vegetation Changes ◽  
Bare Ground ◽  
Forest Regions ◽  
Steep Slopes

The effects of invasion by Phytophthora cinnamomi were measured on sites representing the larger forest regions of the Grampians. Changes were obvious at first, with the death of more than 50% of the species including large plants such as Xanthorrhoea australis, but soon became dificult to detect as susceptible species were replaced by field-resistant graminoids. Reductions were assessed in species heterogeneity and plant density during 1976, at the onset of disease and from 1977 to 1984. Susceptible species disappeared from infested forest and no re-emergence was observed. Less-susceptible plants such as some Euca/yptus spp. declined in number, regeneration and size, due to deaths or dieback of the branches. Reductions in tree canopy and the loss of structural dominants of the understorey caused changes in the flora which are likely to persist. The survival of rare, susceptible endemic species may be endangered. On dry, steep slopes the dead plants were not replaced and the amount of bare ground increased causing erosion of the soil surface. Some graminoid species increased in abundance on level, infested sites, resulting in a different species composition but with both species heterogeneity and plant density numerically similar to the previous flora.

Changes in the Vegetation of Sclerophyll Shrubby Woodland Associated With Invasion by Phytophthora cinnamomi

1981 ◽  
Vol 29 (3) ◽  
pp. 261 ◽  
Author(s):  
G Weste
Keyword(s):  
Plant Community ◽  
National Park ◽  
Plant Density ◽  
Phytophthora Cinnamomi ◽  
Tree Density ◽  
Cyclic Process ◽  
Symptom Expression ◽  
Bare Ground ◽  
Gravelly Soils ◽  
And Control

Changes in the vegetation of a sclerophyll shrub woodland community growing on deep infertile sands at the northern end of Wilson's Promontory National Park were monitored for infected and control plots over a 5- year period and compared with changes due to disease on a ridge site. In all cases disease appeared as a mosaic of chlorotic and dying plants. The plant community changed to an open sedge woodland characterized by a rediction in tree density, loss of susceptible species, an increase in cover by resistant sedges and increased amount of bare ground. There were highly significant changes in plant density for 12 of the 16 species and in the proportion of these species in the total vegetation. The changes are continuing and there is no evidence as to whether they are irreversible or likely to become part of a cyclic process of disease and recovery. Changes in soil temperature and soil matric water potential were monitored continuously during the 5 years and were correlated with changes in pathogen disease potential, symptom expression and deaths. Disease was most severe not on the plots but on nearby ridge sites with exposed shallow, gravelly soils, and in these plant deaths were more frequent and occurred in more species.

Vegetation Changes Associated With Invasion by Phytophthora cinnamomi of Defined Plots in the Brisbane Ranges, Victoria, 1975-1985

1986 ◽  
Vol 34 (6) ◽  
pp. 633 ◽  
Author(s):  
G Weste
Keyword(s):  
Slow Growth ◽  
Phytophthora Cinnamomi ◽  
Vegetation Changes ◽  
Bare Ground ◽  
Shrub Species ◽  
Slow Growth Rate ◽  
Ground Flora ◽  
Resistant Species ◽  
Open Forest ◽  
Vigorous Growth

Changes in plant species composition over a 10 year period were measured by biennial counts of numbers and areas on seven quadrats at each of three sites; one site pathogen free, one in the process of invasion by Phytophthora cinnamomi and one diseased since 1970. Susceptible species died and field-resistant species increased. Partly susceptible species fluctuated in growth. The plant community changed from open forest with sclerophyllous understorey dominated by Xanthorrhoea australis to open forest with large gaps and sedge-dominated ground flora. Tree numbers increased by 25% on the pathogen-free site but decreased by 42.9 and 45.3% on the two infested sites. Susceptible shrub species increased 10% on pathogen-free quadrats but decreased in both numbers and diversity with infestation. The high percentage of bare ground on the old diseased site was gradually colonised by graminoids and legumes. At the end of the 10 year period P. cinnamomi could no longer be isolated from this site, tree crowns showed vigorous growth and seedlings of some susceptible species were observed. The epidemic caused by P. cinnamomi in the Brisbane Ranges may be finite, with peak death periods in 1979 for the invaded site and in 1972 for the old diseased site. The bare ground was later colonised by field-resistant species and the disease potential of the pathogen declined. Regeneration has commenced on the old diseased site and may eventually become complete for the tree stratum, but incomplete for the understorey because Xanthorrhoea australis, formerly dominant, has a very slow growth rate.

scholarly journals Monitoring the effects of pastoral use on upland and high country soils in South Island, New Zealand

1994 ◽  
pp. 233-237
Author(s):  
P.D. Mcintosh ◽  
R.B. Allen ◽  
R. Patterson ◽  
B. Aubrey ◽  
P. Mcgimpsey
Keyword(s):  
Vegetation Changes ◽  
Soil Monitoring ◽  
Bare Ground ◽  
Total N ◽  
Organic C ◽  
Time Period ◽  
C And N ◽  
Fertiliser Application ◽  
Steep Slopes ◽  
Soil Changes

This paper reports on chemical changes that have occurred since 1978 in topsoils (O-7.5 cm depth) of upland and high country farms at 3 sites: Longslip and Glencaim Stations near Omarama, north Otago, and the east Otago uplands between Middlemarch and Alexandra. Between 1978 and 1992 on Longslip, on fertilised and oversown hilly and steep slopes, mean soil organic C increased by 67%, total N value changed little, and pH declined by 0.41 units. Associated with the soil changes were declines in the amount of bare ground and snow tussock cover, and increases in legume and hieracium cover. The organic C change was equivalent to an increase of about 11 t C/ha between 1978 and 1992. Over the same time period no topsoil changes on lower landscape positions were apparent. On Glencairn, under grazing but no topdressing, mean organic C declined by lo%, total N declined by 25% and pH declined by 0.43 units between 1978 and 1993). The organic C and N changes were equivalent to a decline of about 1.7 t C/ha and 0.4 t N/ha between 1978 and 1993. In contrast, within unfertilised and fertilised plots of exclosures that had not been mown or grazed for 9 years, organic C rose by 40-55%, total N rose by 21-36%, and there was no significant change of pH. Vegetation changes outside the exclosures included an increase of hieracium and briar cover. On the east Otago uplands under light grazing and little or no fertiliser application no significant changes of pH, organic C or total N were~recorded between 1978 and 1994. The results show that soil monitoring can give useful information about the changes associated with pastoral use and the options available to maintain or enhance soil organic matter and pH levels. Keywords: high country, monitoring, organic C, pH, sustainability, total N

Alpine and Subalpine Wetland Vegetation on the Bogong High Plains, South-eastern Australia

1999 ◽  
Vol 47 (2) ◽  
pp. 165 ◽  
Author(s):  
C.-H. Wahren ◽  
R. J. Williams ◽  
W. A. Papst
Keyword(s):  
Soil Depth ◽  
Vegetation Type ◽  
Soil Surface ◽  
Wetland Vegetation ◽  
High Plains ◽  
Composition And Structure ◽  
Eastern Australia ◽  
Drainage Channels ◽  
Floristic Variation ◽  
Steep Slopes

The botanical composition and structure of wetland vegetation from seven sites in the alpine and subalpine tracts of the Bogong High Plains was sampled in 1995 and 1996. Sites were in the vicinity of Mts Nelse, Cope and Fainter. Sampling was based on contiguous 1-m2 quadrats along transects 20−70 m long across each wetland. Samples were ordinated using non-metric multidimensional scaling (NMDS). Floristic variation was assessed both within selected individual wetlands, and between wetlands from different regions. The relationship between the ordinations and environmental variables such as soil surface texture, soil depth and the amount of bare ground was tested by fitting vectors. Three dominant vegetation assemblages were identified. Closed heath, of hygrophyllous, scleromorphic shrubs such as Richea continentis and Baeckea gunniana, the rush Empodisma minus and the moss Sphagnum cristatum occurred on the deeper peats. Low open heath of Epacris glacialis and Danthonia nivicola occurred on shallow peats. Herbfields of Caltha introloba and Oreobolus pumilio occurred on stony pavements in two different physiographic situations&horbar;on relatively steep slopes (10−20°) at the head of wetlands, and on flat ground (slope < 2°), below the head of wetlands. The pavements on the steeper sites appeared to be associated with periglacial features such as solifluction lobes and terraces. Those on the flatter ground appeared to have been derived more recently. Wetlands in the Mt Cope region consisted of closed heath, low open heath and pavement herbfield in various proportions. Wetlands on Mt Fainter, which are subject to heavy trampling by cattle, were in a degraded condition, with a low cover of major hygrophyllous mosses and shrubs, and a high cover of introduced species. Long-ungrazed wetlands in a 50-year exclosure at Rocky Valley had high cover of closed heath, no pavements, numerous ponds and virtually no entrenched drainage channels or exposed peat. The Caltha herbfields are significant features nationally, both floristically and geomorphologically. Alpine and subalpine wetlands have been listed under the Victorian Flora and Fauna Guarantee Act 1988, and continued grazing by cattle is not compatible with the conservation objectives for this alpine vegetation type.

Pollen diagrams from interior Labrador

1970 ◽  
Vol 48 (11) ◽  
pp. 1957-1975 ◽  
Author(s):  
Alastair Morrison
Keyword(s):  
Primary Succession ◽  
Vegetation Changes ◽  
Bare Ground ◽  
Radiocarbon Dates ◽  
River Watershed ◽  
Pollen Diagrams ◽  
Glacier Ice ◽  
Lake Waters

Six pollen zones can be distinguished in interior Labrador. The earlier zones represent the primary succession of vegetation from bare ground to boreal woodland or forest, which occupied about 500 years between 5700 and 5200 B.P. There have been only minor fluctuations in the nature of the vegetation since 5200 B.P. Radiocarbon dates show that the zones are contemporaneous over that part of the Lake Plateau within the Churchill River watershed, but similar vegetation changes occurred 1000 years earlier in the Kaniapiskau basin, further north, in New Quebec. These two areas must have been freed of a cover of glacier ice or lake waters immediately before 5700 B.P. and 6700 B.P. respectively.

A structural gradient in cerrado vegetation of Brazil: changes in woody plant density, species richness, life history and plant composition

2002 ◽  
Vol 18 (5) ◽  
pp. 775-794 ◽  
Author(s):  
Luci Ferreira Ribeiro ◽  
Marcelo Tabarelli
Keyword(s):  
Life History ◽  
Species Richness ◽  
Species Composition ◽  
Woody Plant ◽  
Plant Density ◽  
Lower Layer ◽  
Sensu Stricto ◽  
Life History Strategies ◽  
Cerrado Vegetation ◽  
Structural Types

Four structural types of cerrado vegetation were examined to test the following hypotheses: (1) there are predictable changes in woody plant density, species richness and life-history strategies from one structural type to another; and (2) plant species composition in the less-rich structural types represent particular and impoverished subsets of those found in the richer ones. The study was conducted at Fazenda Palmares (5°33′S, 42°37′W) Piauí State, Brazil. A 47% decrease in woody plant density between cerradão (forest) and the least-dense type of cerrado sensu stricto (scrub) was associated with a 40% decrease in species richness. The percentage of lower-layer species was reduced by 29% in the least dense type of cerrado sensu stricto compared to cerradão. The proportion of species that flower and fruit during the rainy season was also reduced by one third. Species were not distributed as impoverished subsets along the cerradão–cerrado sensu stricto gradient. It is argued that the reduction in woody plant density and richness is partly due to factors limiting the occurrence of species with particular life-history strategies. The species composition of structural types is affected by the ‘mass effect’ and also by surrounding biotas, which provide species that colonize particular types of cerrado vegetation. Both these processes reduce the likelihood that the species composition in the poorer structural types are simple subsets of those present in the richer types.

scholarly journals Petrophytic-steppe communities of the Mogutova Mountain (Zhiguli Hills)

2016 ◽  
Vol 5 (3) ◽  
pp. 48-53
Author(s):  
Larisa Valerievna Sidyakina ◽  
Vladimir Mikhailovich Vasjukov ◽  
Sergey Vladimirovich Saksonov
Keyword(s):  
Russian Federation ◽  
Endemic Species ◽  
National Park ◽  
The North ◽  
Steppe Communities ◽  
Feather Grass ◽  
The Russian Federation ◽  
Pulsatilla Patens ◽  
Steep Slopes

The Mogutova Mountain - domal erosive ostanets in the north of the Zhigulyovsk hill, lies in national park Samara Luka. Communities petrophytic steppes are formed on calcareous exposures of steep slopes of the western, southern and east expositions of the mountain Mogutova. Petrophytic-steppe communities on a slope of east exposition are described - petrophytic-forbs-feather grass steppe ( Stipa capillata + Stipa pennata + Herbae stepposae ), on a slope of west exposition - petrophytic-sunrose-feather grass steppe ( Stipa pennata + Helianthemum nummularium ), on a slope of south exposition - petrophytic-thyme-sedge-feather grass steppe ( Stipa pulcherrima + Carex pediformis + Thymus zheguliensis ). In the studied communities three narrow-local of endemic species of the Zhigulyovsk hill grows: Euphorbia zhiguliensis, Gypsophila juzepczukii, Thymus zheguliensis and three of subendemic species grows: Festuca wolgensis s.str. , Tanacetum sclerophyllum (endemics of Central Volga area), Koeleria sclerophylla (endemic of Central Volga area and South Ural); the relict element of flora is presented by three species: Alyssum lenense, Clausia aprica, Helianthemum nummularium . Five species are included in the Red book of the Russian Federation: Astragalus zingeri, Euphorbia zhiguliensis, Koeleria sclerophylla, Stipa pennata, Thymus zheguliensis ; sixteen species are included in the Red book of the Samara region: Adonanthe vernalis, Alyssum lenense, Astragalus zingeri, Clausia aprica, Cotoneaster laxiflorus, Euphorbia zhiguliensis, Festuca wolgensis, Gypsophila juzepczukii, Helianthemum nummularium, Koeleria sclerophylla, Onosma volgensis, Pulsatilla patens, Scabiosa isetensis, Stipa pennata, Tanacetum sclerophyllum, Thymus zheguliensis. The most widespread plants of petrophytic steppes of the Mogutova Mountain: Astragalus zingeri, Carex pediformis, Echinops ruthenicus, Galium hexanarium, Gypsophila juzepczukii, Helictotrichon desertorum, Jurinea ledebourii, Onosma volgensis, Psephellus carbonatus, Stipa pennata, Tanacetum sclerophyllum, Thesium ramosum, Thymus zheguliensis .

scholarly journals First Report of White Mold Caused by Sclerotinia sclerotiorum on Common Sage (Salvia officinalis) in Italy

Plant Disease ◽  
2004 ◽  
Vol 88 (9) ◽  
pp. 1044-1044
Author(s):  
A. Garibaldi ◽  
A. Minuto ◽  
M. L. Gullino
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Plant Density ◽  
Soil Surface ◽  
Salvia Officinalis ◽  
White Mold ◽  
Rooted Cuttings ◽  
First Report ◽  
Streptomycin Sulfate ◽  
High Plant Density ◽  
White Mycelium

Salvia officinalis L. is cultivated as an aromatic ornamental plant in Italy. In the spring of 2003, rooted cuttings grown in containers in commercial farms near Albenga (northern Italy) had soft and watery stem tissue covered with whitish mycelium at the soil level. Leaves and stems showed necrotic areas of irregular shape and size. As necrosis progressed, infected plants wilted and died. Wilt occurred within a few days on young plants. Because of high plant density, the pathogen spread rapidly within and across containers to infect many rooted cuttings. Sclerotinia sclerotiorum (Lib.) de Bary (2) was consistently recovered from infected stem pieces of Salvia officinalis that were disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 ppm of streptomycin sulfate. Sclerotia produced on PDA were ellipsoid and measured 1.4 to 4.2 × 1.1 to 2.1 (average 2.1 × 1.5) mm. Pathogenicity of three isolates obtained from infected plants was confirmed by inoculating 30-day-old plants grown in pots (14-cm diameter). Inoculum of each isolate was 14-day-old cultures of mycelium and sclerotia grown on sterile wheat kernels (300 g) and deionized water (320 ml) in a 1-liter flask at 20 to 25°C. Inoculum (10 g) of each isolate was placed on the soil surface around the base of 10 plants. Ten noninoculated plants served as controls. The inoculation trial was repeated once. All plants were kept in a screenhouse at temperatures ranging between 8 and 31°C and watered as needed. Inoculated plants developed symptoms of leaf yellowing, followed by the appearance of white mycelium within 7 days, and eventually wilted within 12 to 15 days. Control plants remained symptomless. White mycelium and sclerotia developed on infected tissues, and S. sclerotiorum was reisolated from inoculated plants on PDA amended with 100 ppm of streptomycin sulfate. To our knowledge, this is the first report of white mold of Salvia officinalis caused by S. sclerotiorum in Italy. The disease has been observed in Canada (1) as well as Tasmania and New Zealand. References: (1) G. J. Bolland and R. Hall. Can. J. Plant Pathol. 16:93, 1994. (2) N. F. Buchwald. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift, 1949.

scholarly journals Miami-Dade County Urban Tree Canopy Analysis

2021 ◽  
Author(s):  
Hartwig Hochmair ◽  
◽  
Adam Benjamin ◽  
Daniel Gann ◽  
Levente Juhasz ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Urban Development ◽  
Tree Canopy ◽  
Dade County ◽  
Impervious Surfaces ◽  
Vector Data ◽  
Bare Ground ◽  
Urban Tree ◽  
Wetland Water ◽  
Urban Tree Canopy

This assessment focuses on describing urban tree canopy (UTC) within the Urban Development Boundary of Miami-Dade County, as defined by the Miami-Dade County Transportation Planning Organization (Figure 1). The area (intracoastal water areas excluded) encompasses approximately 1147 km2 (443 mi2). A combination of remote sensing and publicly available vector data was used to classify the following land cover classes: tree canopy/shrubs, grass, bare ground, wetland, water, building, street/railroad, other impervious surfaces, and cropland.

Bryophyte species and communities on various roofing materials, Estonia

2021 ◽  
Vol 58 ◽  
Author(s):  
Elle Rajandu ◽  
Tiina Elvisto ◽  
Hanna-Liisa Kappel ◽  
Marko Kaasik
Keyword(s):  
Species Composition ◽  
Rural Areas ◽  
Green Roofs ◽  
Tree Canopy ◽  
Similar Species ◽  
Species Analysis ◽  
Roofing Material ◽  
Species Characteristics ◽  
Fibre Cement ◽  
Roofing Materials

Considering the recent growth of interest in using mosses in creating vegetated green roofs, we set the aim of our study to get an overview of the variety of moss and liverwort species and communities growing spontaneously on roofs. Data were collected from 67 roofs of five different types of materials: fibre cement, bitumen, stone, thatched and steel from Tallinn and rural areas on Hiiumaa Island and in South Estonia. Indicator species analysis, MRPP, cluster analysis and ordination methods (DCA, CCA) were used for data analysis. As a result of this research, generalist bryophytes occurring on all types of roofing materials were studied and bryophyte species characteristics for certain material types were identified. The thatched roofs differed most clearly from the other roof types in their species composition and had the highest species diversity. Stone and fibre cement roofs had similar species composition. The results revealed significant dependence of the composition of the bryophyte flora on roofs on the density of the bryophyte carpet formed over time on the roof and the presence of a tree canopy above the roof. Other important factors were roof relief, the height of the roof from the ground and the indicator of environmental pollution NOx. However, the studied roofs in Tallinn and rural areas did not show significant differences in the species composition of bryophytes. Five communities were delimited: (1) Syntrichia ruralis – Schistidium apocarpum; (2) Orthotrichum speciosum – Bryum argenteum; (3) Brachythecium rutabulum – Hypnum cupressiforme; (4) Ceratodon purpureus – Rhytidiadelphus squarrosus; and (5) Pleurozium schreberi – Dicranum scoparium. The mentioned communities inhabited locations that differed in environmental conditions. The findings of this research can help choose the roofing material and species suitable for a certain location in creating moss greenery on roofs.

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